Lining for grinding apparatus and the like



June 29 192.

. H. N. s|= |c:Er-e

LINING FOR GRINDING APPARATUS AND THE LIKE Filed Dec. 1'7. 1925 INVENToR s :Wl ylmlczm,

A TTORNE YS LUHNG FOR GRINDINGPRATUS AND THE LIKE.

Application led December 17, 1925. Serial N10. 75,984.

rllhis invention relates to linings for grinding apparatus, and the like, and has for its object the provision of an improved lining for such apparatus and more particularly an improved acid-resistant lining for apparatus used in indinfr (such, for example, as ball millsrdissolsving, precipitating, and other operations.

arious expediente have heretofore been employed for providing ball mills and similar apparatus with acid-resistant or acidproof lining. Metallic lead is substantially resistant to the action of many acid liquors, and on this account, lead has been most generally employed heretofore as the acid- ,resistant lining oi ball mills and similar apparatus. lin attaching a coating or lining of lead (generally in sheet form) to a metal Surface (such as iron or steel), the metal is usually rst heated to the melting point ot lead. lln some cases, theshect 'of Ilead is burnt onto the metal shell at various points by means of a blow torch. ,The iirst method is soexpensive as to be impracticable with ball mills more than about three feet in diameter, While the second methodgives a coating which is not rigid and which is'very lirelly to become-dislodged from the metal s e l. e

Since lead is a relatively soft material, it does not satisfactorilyl withstand the abrading action which takes place in a ball mill.

@n this account, the lead lining has been sometimes protected by a layer of silica brick. ll'have found that these bricks exercise a hammering action upon theclead linlayer of wood, or equivalent material, be-

tween the acid-resistant lining .and the cooperating abrasi'on-resistant protective layer or lining. ln its preferred aspect, the invention involves anacid-resistant rubberv A to a rotatably mounted shafti20. A pulley lining appropriately secured to the metal iron.

shell of the apparatus over which is placed a layer ot wood, or the like, the latter being covered with a protective layer of silica brick, or the like, laid in acid-proof cement.

l' prefer rubber 'as the acid-resistant material in the improved lining of my present invention, but it 'will of course be understood that lead and equivalent acid-resistant materials may be employed if desired. An acid-resistant rubber or rubber compound should pf course be employed in apparatus requiring an acid-proof or acid-resistant lining. To this end the crude rubber. should be compounded and/or lvulcanized with vagents which will produce a rubber compound -satisfactorily resistant to the particular acid characteristics of the material to "be treated in the apparatus. llt is not necessary thatthe rubber lining be particularly resistant to abrasion since it is protected in the first instance by the outer layer or lining of silica brick as well'as by the intermediate Vlayer of wood or similar material. Accordingly, it is possible inaccordance with the presentinvention-to employ a rubber lining possessing optimum properties with respect to attack by acid l'quors, and thereby obtaining tlie best podl sible acid-proof or acidresistant lining for the'particular apparatus in hand.

ln the accompanying drawing l have illustrated a ball mill embodying the novel features of the present invention in what I now consider the preferred form thereof. ln the drawing f Fig. l is a sectional elevation ofthe apparatifs l Fig. 2 is asectional view on the line 2--2 of Fig. l; and

Fig. 3 is an enlarged detail View of the metal shell and my improved lining.

The ball mill illustrated' 'n the drawing comprises a cylindrical metal shell 'i' to the ends of which are bolted headers" or end plates 5 and provided with trunnions 3vr and 4.. These elements are easily made of an easily workable metal, such as steel or mounted onl the foundations 1. The shell 7 is provided with a manhole normally closed b}y1acover l7 appropriately bolted to the seL A circular rack'lS is secured to the shell? and operatively engages a gear 19 secured rlhe trunnions are appropriately?J -21 is secured to the shaft A20, and when driven froman appropriate source of power serves to rotate the mill at the desired speed.

In accrdance with my present invention the. interior surface of the ,shell 7 is covered with a lining 12 of acid-resistant rubber or equivalent material. Similarly the interior for ordinary purposes.

various exposed parts of the mill. In A.the

case of rubber, l lind a layer of aboutonefourth of an inchv in thickness satisfactory may be applied to the shell in any appro- -priate manner as, for example, by vulcanization in situ.

The aeid-resistantlining 12, preferably of rubberis covered with a layer or shell 13 of wood, ,or equivalent material. For this purpose boards from one-half inch to about one inch in thickness by three inches wide and of appropriate length may be used. These boards are preferably held in place by Wedging, thus' avoiding the use of bolts,

rivets, and similar metallic fastening means.

.This Wooden construction covers the acidresistant lining on the shell 7, the headers '5 and 6, andthe trunnion 4, and if desired,

may also cover the acid-resistant lining on the trunnion thus protecting allexposed` portions of the lining from the layer of bricks subsequently applied..

*An abrasive layer or lining 14 of silica brick is laid on the Wooden shell 13. The silica bricks arelaidin a suitable acid-proof ycement and `'cover such parts of the apparatus as in operation are exposed to abrasive action, such as the interior of the shell 7 and headers 5 and 6. The manhole 17 is-also lined with the three layers of acid-resistant material, protective material,l and abrasive material.

The manhole frame and rmanhole 4cover -17 as well as other relatively small and easily replaced parts of the apparatus, such as the feed or inlet pipe 15 and the, discharge or outlet pipe 16, are made of bronzalum or other suitable acid-proof material.

The operation of the mill is as follows. A charge of balls, rocks, or other material to be used as a grinding medium is first placed in the mill through the manhole or throiigh the feed pipe. The mill is then rotated at the desired speed. The solids to .be ground withthe acid or other liquor are fed into the mill continuously by means of a feed scoop 11 secured to the trunnion 3 by means of a suitable casting'lO. i'lhe feed scoop 11 thus rotates with the mill and dips into a feed trough (not shown), When' the level of the material in the mill has risento the lower lip of discharge pipe 16, the

The rubber lining discharge of material f/rom the mill maybe controlled by the ambunt of material fed thereto. The grinding in the mill results from the rumble action of the balls on the solids in the mill as Well as 'from the natural attrition of the solids on each other. The greatest amount of abrasive action occurs in the cylindrical portion of the mill, and considerable abrasive action occurs in the ends of the mill; hence these parts of the mill sare protected by the J abrasin-resistant layer or lining 14. a

' It is to be understood that the present invention is not restricted to grinding apparatus, but may be advantageously applie to apparatus of various types. For example, in the precipitation of copper from solution by iron in an acid leaching process, one method commonly used is" to ll an apparatus of -the type herein particularly described With small pieces or chunks of iron and cause the copper-bearing solution to flow in at one end and out at the other end.'

The copper is precipitated on the iron and the abrading action of the chunks of iron on each other knocks the precipitated copper loose'so that it is discharged by the liquid flow and subsequently recovered by settling. An apparatus employed for this purpose may very advantageously be provided with the improved lin-ing of' my present invention.

torily used as the inner abrasion-resistant` lining. It will of course be understood that theabrasion-resistant lining need not be constructed of bricks or blocks, but may be, in whole or in part, a continuus or monolithic layer of appropriate thickness. In additlon, my present invention involves the interposition of the layer or shell of wood,

` or equivalent material, between the acidresistant lining and the abrasion-resistant limng. The wooden lining or shell distributes the pounding or hammering effect of the abrasion-resistant lining over .substantially the ent/ire surface of the acid-nasistantv lining, and thereby effectively prevents dislocatlon, excessive wear, puncture, and other vinjuries to the relatively soft acid-resistant lining. By means of this construction a very satisfacto acid-resistant or acid-proof lining is provi ed, and at the same time the inner or contacting surface of the mill is set gard and resistant to abrasion for practical urposes.l

From the foregoing description it will bedeo I claim-4. 1; In an apparatus of the character descrlbed, a linin comprising a layer of acidresistant material, protected by a layer of abrasion-resistant material, and a layer of fibrous material interposed between said acid-resistant layer and said abrasion-resistant layer. p

2. In an apparatus vof the character described, a lining comprising a layer of relatively soft acid-resistant material, protected by' a layer of abrasion-resistant material, and means positioned intermediate said two lresistant material upon said other material layers for distributing the action of vthe abrasion-resistant layer substantially uniformly over the acid-resistant layer.

3. In an apparatus of the character described, a lining comprising a layer of acidresistant material, a layer of abrasion resistant material superposed thereon, and means whereby the wear action of the abrasion-resistant layer upon the acid-resistant layer is distributed substantially uniformly over thesurface of the acid-resistantlayer.

4. In an apparatus of the character described, a lining comprising a layer of acidresistant rubber protected by a superposed layer of abrasion-resistant material.

5. Inan apparatus of the character described, a lining comprising a layer of rubber, a layer of abrasion-resistant material superposed on said la er of rubber, and

means intermediate sai two layers for uniformly distributing the wear of said abrasion-resistant material on said rubber layer substantially uniformly over the surface of the layer of rubber.

6. In an apparatus of the character described, a lining comprising a layer of relatively soft material, protected by a superposed layer of abrasion-resistant material, and means interposed between said layers for distributing the wear of the abrasionsubstantially uniformlyv over the surface 'of said other material. V

7. In anapparatus of the character de# scribed, a lining comprising a layer of rubber, a layer of abrasion-resistant material superposed thereon, and a layer of fibrous materialV interposed between said layer of rubber and said layer of abrasion-resistant material.

8. In an apparatus of the character described, a linmg comprismg a layer of relatively soft material, protected by a superposed layer of abrasion-resistant material in the form of bricks, and means interposed, between said layers for distributing the wear of the abrasion-resistant layer on said other layer substantially/uniformly over the surface of said other layer.

9. In an apparatus of the character describedsa lining comprising a layer of relatively soft material, protected by a su erposed layer of abrasion-resistant materia in the form of bricks, and a layer' of fibrous material interposed between the relatively soft layer and the abrasion-resistant layer.

10. In an apparatus of the character de-Y scribed, a lining comprising a layer of acidresistantrubber, protected by a superposed layer of abrasion-resistant materialjin lthe form of bricks, and a layer of fibrous material interposed between said layer of rubber and said layer of abrasion-resistant material.

11. In an apparatus of the character de-A' scribed,a lining comprising a layer of afidresistant rubber, a layer of silica bricks superposed on said layer of rubber, and a layer of fibrous material interposed between said layer of rubber and said layer of silica bricks.

In testimony whereof I atx my signature.

nanou) NORMAN sricsn. 

